Crossfire APU & GPU speeds

[Lawrence_b_rfc]

When creating a build with an APU such as the A10 7870K and a GPU such as the R7 370, how do the two cooperate with each other. What do I look for when buying a card to work in crossfire with this APU, is it the core clock speed and the IGPU base clock? Does the memory come into account considering the GDDR5 and DDR3 memory that I would buy at 2400MHZ,

I would like an explanation of how it works, if anybody can help

FYI I have an i5 and GTX 750ti that suits me fine, I am looking into building a build like this for my brother

 

[Poprin]

I have limited experience with dual graphics, however when I was researching this some months ago the realistic best option was a DDR3 based R7 250. The problem is, a faster card and especially something with GDDR5 is just too quick for the APU to catch up. I can understand why you would want to experiment with this as I've considered doing it for my HTPC with a silent card but if it is for gaming you do know that it's never going to be faster than an Athlon and an R7 370. If you can budget an R9 380 and an Athlon 860k it would literally destroy it in gaming.

 

[unreal9400]

A-SERIES NAME APU GRAPHICS BRAND RECOMMENDED GRAPHICS CARD PAIRINGS
A10 – 78x0 APUs AMD Radeon™ R7 AMD Radeon™ R7 250
A10 – 6xx0 Series AMD Radeon™ HD 8670D AMD Radeon™ HD 6570, HD 6670
A10 – 7700K
A8 – 76x0
AMD Radeon™ R7 AMD Radeon™ R7 240
A8 – 6x00 Series AMD Radeon™ HD 8570D AMD Radeon™ HD 6570, HD 6670
A6 – 6x00 Series AMD Radeon™ 8470D AMD Radeon™ HD 6450